diff --git a/Documentation/thermal/sysfs-api.txt b/Documentation/thermal/sysfs-api.txt
index 895337f..a87dc27 100644
--- a/Documentation/thermal/sysfs-api.txt
+++ b/Documentation/thermal/sysfs-api.txt
@@ -199,6 +199,15 @@
 	point.
 	RO, Optional
 
+passive
+	Attribute is only present for zones in which the passive cooling
+	policy is not supported by native thermal driver. Default is zero
+	and can be set to a temperature (in millidegrees) to enable a
+	passive trip point for the zone. Activation is done by polling with
+	an interval of 1 second.
+	Unit: millidegrees Celsius
+	RW, Optional
+
 *****************************
 * Cooling device attributes *
 *****************************